Mark,

Wasn't that early 19th century downward trend the result of volcanism.

Tambora/Krakatoa-type events generally are on a short time scale - less than a decade (viz. Pinatubo). And yes, AIUI several factors including increased volcanism, solar irradiance changes, Industrial Revolution particulates and rapid, large-scale land-use changes (forest clearing for fields and pasture, which increases albedo and increases particulates) worked together for perhaps a ~.3ºC decrease in the early 19th C global temps (outlined, e.g. here). In nature, almost always, change in inertia and energy in systems arises from multiple causative factors. Same in the 19th C.

Some of the discussion of afforestation to sequester C as a mitigation technique has concerns about lowering albedo, and such discussions refer to the land-clearing of the 19th C as evidence.

Take care Mark.

Dan

I think the original question was about heating and insulating the greenhouse, wasn't it? I don't think we're going to solve the debate about is it global warming or cooling or anyting here in this forum!
Have you considered that foil backed bubble wrap? It's kind of expensive but lasts a long time and any heat inside the area will keep bouncing around in there instead of going outside.I've heard it's really good to insulate roofs of buildings with. The kind I saw was called tekfoil from farmtek.com

Sandy, Just think of the earth as a big greenhouse and the greenhouse gases as the bubble wrap. With that in mind I think you can see that Dan and I were right on topic. Just kidding.

I doubled the polyethylene in my solar greenhouse (only the south wall and south roof are glazed) 3 days ago and it has improved the differential by 5-7 degrees. Nights are 18-20 outside, 45-46 inside. I'm still planning to install 1,000 gallons of water for the mass I need for thermal storage and to hopefully moderate daytime temperatures. 108 the other day inside w/o blower operating (yes, in the shade) 36 outside at 1:45, so vents will be next. It seems a shame to vent out BTUs that should be captured.

Mark

"Posted by sandy0225 z5 Indiana -------I think the original question was about heating and insulating the greenhouse, wasn't it? I don't think we're going to solve the debate about is it global warming or cooling or anyting here in this forum! ----"

This is a very low activity forum, I certainly do not mind some off-topic discussion going on. I have found this thread to be extremely educational.

If the origianl poster has an objection, please speak up.

Thank you Dan and Mark, please continue.

dcarch

Actually, I'll only need one or two more posts and I'll have Dan agreeing with me. It's really been going my way, haven't you noticed.
Mark

In that case, I will start to make some trouble. :-)

I have been curious as to how much impact on earth climate due to the following:

1. Saddam's burning of the oil fields.
2. Forest fires.

dcarch

First of all, Mark, do you have a website for your GH? I'd like to tour it. Once we move out of this horrible McSuburb and get a decent-sized parcel, I'm going to build a straw-bale solar GH (scaled up from my coldframe).

I have been curious as to how much impact on earth climate due to the following:
1. Saddam's burning of the oil fields.
2. Forest fires.

1. Just a regional event. We have a NatGeo around here somewhere with good fotos, and the particulates maybe affected several thousand km2, not enough to affect global atmospheric processes.

2. Excellent question that many are trying to get their hands around. My undergrad is in Urban Forestry so we had to study a lot of tree stuff, so this is a passion.

First, C is released and not sequestered and thus re-enters the active cycle. Second, large burns do not appear to show on the {{gwi:286668}} variations due to seasonality. Third, particulates in the atmosphere from, say, Borneo or Indonesia fires do affect total atmospheric transparency and albedo. Fourth, deforestation affects the water cycle and we see this in the Amazon, which has areas that are drying and warming, and the water vapor disseminates into the larger atmosphere. Fifth, albedo changes with deforestation (for soya in Brazil, e.g.), increasing albedo and cooling (but increased energy at surface warms, so net warming). But quantifying a sign and net effects? Not there yet. IMHO.

Dan

Thanks, this is the most interesting thread on the GH forum in some time.

I don't have a greenhouse site but I do have a business site- lindmarkhomes.com. I am the enemy. I design and build homes. For 31 years in Southwest Colorado. Although, given the depression in my industry, I could call myself a recovering builder. And worst of all- I'm a freedom first libertarian. I know, boo. Hiss.

I am excited about my new greenhouse and as soon as I finish converting Dan I'm going to address the issue of water thermal storage.

Cheers all,

Mark

Has anyone used steel barrels or steel containers for water thermal storage? What did you use for a rust inhibitor, preferably non toxic but not too expensive.

Mark

1. Paint?

2. I think a heavy duty trash bag is water-proof.

3. Sacrificial Anode protection.

I don't generally like water thermal storage because water does not have a lot of thermal capacity and real eatate is so valuable inside a greenhouse.

dcarch

Water is the best cheap substance for thermal storage, isn't it? Twice the thermal storage of earth materials. I know there are other substances available e.g.glauber salts that offer much more thermal storage per volume unit but they're expensive.

Mark

I don't generally like water thermal storage because water does not have a lot of thermal capacity and real eatate is so valuable inside a greenhouse.

!

Where on earth did you get this idea?!

Rust is one reason why many are moving away from steel drums, and the other is you want square containers for more contact with adjacent units. There should be numerous food-grade poly-based containers available, albeit down there it might take a while to procure. Try talking up some restaurants-pubs and see what they have. Craigslist maybe.

Dan

Water is the best cheap substance for thermal storage, isn't it? Twice the thermal storage of earth materials.

Much more than twice:

{{gwi:286685}}
Figure 1. Comparative volumes for the same amount of heat storage using three different storage materials.

Dan

Dan, Aren't there some phase change materials that offer 10 or more times the thermal storage of water? I can't find a supplier online to compare the pricing of this substance to a simple 55 gal drum, painted black. Those are $25 each. It'd be fun to experiment with the phase change materials.

Anyone tried this stuff? Is it cost prohibitive?

I see it's melting point is 90 (F). So what does that mean on the other side, when I want the thermal mass to moderate the daytime inside temperatures. Same thing?

Mark

No disagreement with water is cheap and better than some other materials. However based on:

one degree F = 1 BTU / Cubic foot, that's not much heat for a greenhouse.

Water is better in keeping things from freezing because the latten heat of phrase change is greater (Don't remember the BTUs at this point).

Interestingly, water will give you BTUs during the cold night, but it will also take away BTUs from your greenhouse during the day. Depending on your location and climate and the purpose of your greenhouse, this may not be a good thing.

dcarch

That is consistent with what I've learned.

So, what's the solution?

Mark

Interestingly, water will give you BTUs during the cold night, but it will also take away BTUs from your greenhouse during the day. Depending on your location and climate and the purpose of your greenhouse, this may not be a good thing.

Water moderates temp and taking heat during the day - esp if venting - isn't much of an issue unless its cloudy. And where we are, it is an issue for maybe 8 days. And it is free, which is why it has been used for so long. Chemical phase-changing schemes are money. I'd say in Mark's GH he'll need maybe 5-8 nights of extra energy expenditure. I'm not sure spending the money on chemicals AND electric heat is the answer, personally.

Dan

I agree with dcarch. Water without phase change is largely ineffective and not worth the space in the GH IMHO, based on my testing. It gives up most of the BTUs before they are needed.

If you are willing to let the GH drift down to near freezing, then the phase change can be advantageous. If you want to keep Satsumas and bananas, not so much.

"Posted by markmahlum (My Page) on Thu, Jan 14, 10 at 18:46

That is consistent with what I've learned.
So, what's the solution?

Mark"

Crazy idea:
Find out if you know people who get medications thru the mail. Many medications require cold gell packs, which get thrown out.

dcarch

Glauber salts melt at 90 degrees F. Must it change to a liquid state before it gains BTUs? Water begins acquiring heat when the metal jacket temperature surrounding it exceeds it's temperature. So what about the day with a modest amount of sun? Will the water warm up relative to the sun's radiation while the glauber salts only acquire room temperature? I guess that depends on the physical properties of glauber salt, of which I know zero.

And, as for the capture of heat during the day, is the reverse true?

Only Herr Glauber knows, I fear. And he died a long time ago.

On the other hand don't forget, 55 gallon steel drums cost $25. I must haul them a distance of 60 miles round trip in an 18 mpg gas guzzler. 18 barrels means 3 loads. Rust inhibitor will help but the life expectancy is undoubtedly much less than the glauber salts, thus there is depreciation and rust inhibitor cost, which annually needs refreshing. I haul water at a cost of a cost of 4.2 cents per gallon. 42 bucks.

Now I'm at $692 and haven't included depreciation. Thank God I work for free.

A company that sells phase change thermal energy storage materials is supposed to contact me with prices.

Mark

By the way, if my 58 year old geezer memory serves me correctly one BTU raises the temperature of one pound of water one degree F. One cubic foot of water is sixty some pounds, I think.

"----Mark

By the way, if my 58 year old geezer memory serves me correctly one BTU raises the temperature of one pound of water one degree F. One cubic foot of water is sixty some pounds, I think. ----"

You are correct. My brain cells function less effectively in cold temperature. I shall imerge my head in water.

dcarch :-)

I agree with dcarch. Water without phase change is largely ineffective and not worth the space in the GH IMHO, based on my testing. It gives up most of the BTUs before they are needed.

Right. All this is dependent upon what question do we want to answer: do I want to prevent freezing, or do I want to have an adequate temperature for growth and soil temperature? If it is the latter, then water is inadequate and something else is needed.

And again, sunlight and heat gain is not an issue for Mark, at his altitude and in his climate. Even in the winter there will be many days where he will be venting heat, so what to do with it, and at what cost?

Dan

If it is the latter, then water is inadequate and something else is needed.

How about critters. Rabbits, chickens or ducks. I believe they all produce about 8 BTUs.

Anna eddey's book, Solviva has many interesting ideas.
Her north wall is a water wall. Double black plastic garbage bags sandwich between two studed walls.

Eric

Here is a link that might be useful: Solviva

another link with photos

Here is a link that might be useful: Waterwall

A couple of side notes- outside temp at sunrise today, 18. Inside, 39. Thermometer is on the floor, well away from the black masonry wall. I have one water filled clear poly container of 65 gallons.

I've filled two, one gallon plastic containers with water. One is clear, one is painted black. Both are in full sun at six feet above the floor. At sunset I've measured temps of each. The black container runs between 12 and 15 degrees warmer than the clear one. Not scientific by any stretch, but interesting. GH temp has been as high as 108 (last week) while outside temp was 36.

With all other variables being equal, how much more solar radiation do I have here at 7400' versus sea level?

A water wall requires full sun, thus it is a space eater as well. You can't arrange plants to shade it. Or am I misunderstanding the concept.

Mark

Mark

Nope, my food coloring-dyed water is lifted up off the ground and I can't plant tall stuff in front of it, so it takes up space, definitely. Nothing has frozen here this year and I quit measuring the soil when I was satisfied it was in hi 50s-mid 60s consistently.

There you can count on 300 days of sun, and looking at your atm {{gwi:286669}}, eyeballing that airmass looks like you have ~30% less atmosphere to intercept solar radiation than sea level. Looking at some RAWS stations ~around there that measure solar radiation, you get about 10-15% more than I do here at 5700 ft.

Dan

Back to phase change as a system of thermal storage. Water is a phase change material, by definition. solid-liquid-vapor. It's cheap but can't be heated to a vapor state, or phase if you will by passive solar. (202-3 if I recall at my elevation). So, then what?

I currently have some 270 cubic feet of earth materials for thermal storage and I'm seeing an inside outside differential (delta number, I guess) of 20-25 degrees at the coldest time of day.

I can install 15- 55 gallon water filled barrels on the north wall- half with solar exposure, half w/o. That puts the bottom of my plant containers at 32-34" off the floor. They'd sit on planks directly on the barrels. A 40-42" wide bed. I'm 6'2" so that's ok. Shading of the plant tops wouldn't be a problem. Sitting on warm barrels would help soil temp. Shading of masonry wall and floor rock would cost me a third of my earth material thermal mass.

That would leave a 2' 6"x 19' strip on the south wall to set containers of plants that prefer cooler conditions. They'd sit on the floor. I haven't measured floor rock temp but the foundation is 32" deep with R 10 perimeter foambd. insulation. I want to grow cool weather and warm weather crop in GH at the same time so I must create 2 climate zones. Probably impossible.

Now I have incredible temperature stratification but once I add ventilation that will reduce significantly. Water would be 110 cu ft. Not all barrels receive direct sun-8 will. Seven will sit behind and will offer some moderation but not sure how much or how to calculate that.

I'll probably nearly double my thermal storage (7 shaded barrels is the problem) by adding 825 gallons of water.

What works best, steel barrels painted black or clear plastic with dyed water?

I am having trouble finding a supplier of suitable phase change materials.

Mark

The Solar GH Book sez 1 gal/ft2 in your area minimum. Again, you just need to avoid freezing at night and then you need to heat up your water during the day. Most days should do this no problem. Square containers have better contact to transfer heat.

Your floor beds should be warm enough if the sun shines on them for several hours and heats up the soil. You can only grow the seasonality of crops in a truly solar GH. If you are going to change seasons, you need energy and if you do that, there is your heat problem solved. Black barrels are darker than colored water. I have a buddy who put in PEX-type tubing in his floor and circulates water around via a solar pump, helping heat the GH.

Dan

"Posted by markmahlum ----Back to phase change as a system of thermal storage. Water is a phase change material, by definition. solid-liquid-vapor. It's cheap but can't be heated to a vapor state, or phase if you will by passive solar. (202-3 if I recall at my elevation). So, then what? ----------"

Just for the fun of discussions:

Water phase change is dependent also on pressure. In other words, if you pressurized the container, water will not boil at 100 degrees C, and if the container is less than atmospheric pressure, water can boil.

dcarch

Clicked too fast:

Water phase change is dependent also on pressure. In other words, if you pressurized the container, water will not boil at 100 degrees C, and if the container is less than atmospheric pressure, water can boil at below 100 degree c.

Frozen water can go thru phase change from solid to vapor state, known as sublimation, and the opposit can happen known as deposition, that is from vapor to solid without going thru liquid state.

dcarch

We live at 7400'. D.O. pressure, our boiling point is about 198. Our summer cabin is at 10,700'. Boiling point is around 188-189.

I'm such a bad cook that I can barely boil water. However, at our cabin I'm known as a gourmet chef.

Mark

Mark,

"I can install 15- 55 gallon water filled barrels on the north wall- half with solar exposure, half w/o. That puts the bottom of my plant containers at 32-34" off the floor. They'd sit on planks directly on the barrels. A 40-42" wide bed. I'm 6'2" so that's ok. Shading of the plant tops wouldn't be a problem. Sitting on warm barrels would help soil temp. Shading of masonry wall and floor rock would cost me a third of my earth material thermal mass".

This is a photo of my brothers greenhouse. I built this raised bed on top of 5 gallon square containers. The water has black pond dye in them. The only thing seperating the soil from the container tops is woven weed barrier.

Do you think wraping the outside of the containers with black material will help?
Photo Oct. 2009
{{gwi:286686}}

I could get around 5 30 gallon barrels on the east side of my greenhouse. Would that help me very much.

"Posted by markmahlum --------
I'm such a bad cook that I can barely boil water. However, at our cabin I'm known as a gourmet chef.

Mark"
Mark,
Go to the "Cooking" forum here and do a search of "dcarch"
You will see I post a lot of cooking ideas.
Some may encourage you to feel that cooking is no big deal.

dcarch

Thanks ericwa. A picture is worth a thousand words. That is basically want I've intended to do since the inception of my GH project. What is the life of plastic vs. steel (uv degradation vs. corrosion). What about the containers in back that don't receive direct sun. Do they pick up some BTUs? They'd last longer, though. Metal would work better for heat exchange from front containers to shaded ones, or is that even a consideration?

I have access to steel drums but I don't know of a local source for plastic containers.

dcarch,

Thanks for the tip. The saddest part of this is that my wife Linda, is a worse cook than I. The only dish she can prepare is chicken parmigiana minus the chicken and mozzarella. One good thing, though. We raised 3 daughters and they all preferred to eat at friends' houses. Really helped with grocery bills.

I'd like to post a picture on this forum but I am so computer illiterate that I don't know how. Today, if you want to know what my GH looks like, take a blank piece of white typing paper and look at it. That's how it looks to me right now from the house. Big snowstorm.

Mark

Posted by dan_staley USDA 5b/S 2b AHS 6-7

"Rust is one reason why many are moving away from steel drums, and the other is you want square containers for more contact with adjacent units. There should be numerous food-grade poly-based containers available, albeit down there it might take a while to procure. Try talking up some restaurants-pubs and see what they have. Craigslist maybe".

I've been collecting square 5 gallon containers from the water treatment plant. They stack them outside with a free sign. Unfortunately they have switched to traditional round pails, but they are still free.

Eric

Posted by markmahlum (My Page) on Tue, Jan 19, 10 at 10:09

"I'd like to post a picture on this forum but I am so computer illiterate that I don't know how. Today, if you want to know what my GH looks like, take a blank piece of white typing paper and look at it. That's how it looks to me right now from the house. Big snowstorm"
Mark

I'm looking at the paper, I was always told that's a polar bear in a snow storm. Hmmm. :~)

Alright give me your hand. (not) I'll walk you through the scary photo posting.

Eric

When I wrote that post this morning, you couldn't have seen a hairless polar bear at fifty feet.

Mark

I've been collecting square 5 gallon containers from the water treatment plant.

That's about the perfect size and shape for GH heating: the size is small enough to avoid stratification and the shape allows good contact with neighbors to transfer heat. Painting flat black is the best method.

And eric is living just about in paradise, AFAIAC. Little more sun and you'd be overrun with people.

Dan

I think plastic is the way to go. Square, while presenting more surface and better utilizing space will be hard to come by. I have a bunch of plastic 5 gallon pails left over from my construction projects. Maybe that will work while I locate square ones.

Mark

"And eric is living just about in paradise, AFAIAC. Little more sun and you'd be overrun with people".

Dan
Shh keep your big yap shut, it's our little secret. It's funny, I keep hearing people call it the banana belt. No! the Islands are in a Rain Shadow. Dryer, not warmer.

{{gwi:286687}}

{{gwi:286688}}

Only concern I have with painting the containers is flaking off. Maybe roughing up the surface would help.

Dan,
The subject about the ice cube in the water glass. I'm about 45ft above sea level. I'm worried about the big ice cube in the large water glass.

Mark,

Do you upload to Photobucket or flickr or any other photo web site?

Eric

Dan,

How do you change the font when you are quoting someone?

Eric

Here is a piccie of me on a bike tour around the San Juans:

{{gwi:286689}}

If you squint hard enuf you can see Baker over my shoulder. The islands may be in a rain shadow, but they still get cloudy; that and the land prices probably keep most away except to visit and gawk at the beauty. Keeping this marginally OT, I also gawked at a number of solar greenhouses on that bike tour as well. There and Camano you can make a go of it off the land (if you can afford the land to begin with).

Eric, I use HTML code to change font, indent, embed pics and links, change font color, etc.

Dan

If you squint hard enuf you can see Baker over my shoulder. The islands may be in a rain shadow, but they still get cloudy; that and the land prices probably keep most away except to visit and gawk at the beauty. Keeping this marginally OT, I also gawked at a number of solar greenhouses on that bike tour as well. There and Camano you can make a go of it off the land (if you can afford the land to begin with).

Eric, I use HTML code to change font, indent, embed pics and links, change font color, etc.

Dan
Fun, Learn something everyday.

Eric

Hey Dan - why not use some code to reduce your mug-shot to less than 1,772 pixels wide . . . ;^)

eric,

Huh? What's that? I have a Mac. Does that work?

Dan,

I've hiked into most of the lakes in the San Juan Mtns. but I can't place that one.
Looks pretty murky. Must be a low elevation irrigation reservoir.

Mark

I've hiked into most of the lakes in the San Juan Mtns. but I can't place that one.
Looks pretty murky. Must be a low elevation irrigation reservoir.

Mark
Go west young man and north. San Juan Washington.

Eric

Mark,

Go to the link below. Sign up. Then up load your photos. After the photos are uploaded. You cut and paste the HTML code into the message block.

{{gwi:286690}}
Eric

Here is a link that might be useful: Photobucket

Another source for square containers.

Check with your Fire Department. A few days ago my brother came home with about 30 blue square containers. A foam concentrate container.

Eric